100 lines
3.8 KiB
C
100 lines
3.8 KiB
C
/*---
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This software is copyrighted by the Regents of the University of
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California, and other parties. The following terms apply to all files
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associated with the software unless explicitly disclaimed in
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individual files.
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The authors hereby grant permission to use, copy, modify, distribute,
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and license this software and its documentation for any purpose,
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provided that existing copyright notices are retained in all copies
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and that this notice is included verbatim in any distributions. No
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written agreement, license, or royalty fee is required for any of the
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authorized uses. Modifications to this software may be copyrighted by
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their authors and need not follow the licensing terms described here,
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provided that the new terms are clearly indicated on the first page of
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each file where they apply.
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IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY
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FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY
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DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
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INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND
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NON-INFRINGEMENT. THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, AND
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THE AUTHORS AND DISTRIBUTORS HAVE NO OBLIGATION TO PROVIDE
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MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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GOVERNMENT USE: If you are acquiring this software on behalf of the
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U.S. government, the Government shall have only "Restricted Rights" in
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the software and related documentation as defined in the Federal
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Acquisition Regulations (FARs) in Clause 52.227.19 (c) (2). If you are
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acquiring the software on behalf of the Department of Defense, the
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software shall be classified as "Commercial Computer Software" and the
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Government shall have only "Restricted Rights" as defined in Clause
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252.227-7013 (c) (1) of DFARs. Notwithstanding the foregoing, the
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authors grant the U.S. Government and others acting in its behalf
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permission to use and distribute the software in accordance with the
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terms specified in this license.
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---*/
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#include <stasis/logger/logger2.h>
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#ifndef __LOGHANDLE_H
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#define __LOGHANDLE_H
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BEGIN_C_DECLS
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typedef struct LogHandle LogHandle;
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/**
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@file
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Iterator for forward and reverse iterations over the log. Forward
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iterations are used for redo and return each log entry in log
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order. Reverse iterations are used for undo, and return each entry
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in a particular transaction. They follow the prevLSN field,
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skipping any undo entries that have been marked complete.
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The memory that contains the logEntry objects is managed by the LogHandle.
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Callers should not free() or otherwise dispose of memory returned by a LogHandle.
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@see logWriter.h For write access to the log.
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@see logger.h For the api provided by log implementations.
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*/
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/**
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Allocate a logHandle pointing at the first log entry in the log.
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*/
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LogHandle* getLogHandle(stasis_log_t* log);
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/**
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Allocate a logHandle pointing at a particular lsn.
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*/
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LogHandle* getLSNHandle(stasis_log_t* log, lsn_t lsn);
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/**
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Free any resources associated with a LogHandle object.
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*/
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void freeLogHandle(LogHandle* lh);
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/**
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@return a pointer to the next log entry in the log, or NULL if at
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EOF.
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*/
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const LogEntry * nextInLog(LogHandle * h);
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/**
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Returns a pointer to the previous log entry in this transaction.
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If we encounter a CLR, that means that everything after the clr's
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prevLSN has already been undone. Therefore, we skip all
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intervening log entries (including CLR's), since they contain
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obsolete data.
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@return NULL if there is no previous LogEntry for this transaction
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*/
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const LogEntry * previousInTransaction(LogHandle * h);
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END_C_DECLS
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#endif
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